tailieunhanh - Nonlinear Optics - Chapter 13

Ultrafast and Intense-Field Nonlinear Optics Hiện nay rất quan tâm đến vật lý của các xung laser siêu ngắn. Tiến bộ gần đây đã dẫn đến việc tạo ra các xung laser với thời gian của 1 atto giây. Xung siêu ngắn có thể được sử dụng để thăm dò các thuộc tính của vật chất trên quy mô thời gian rất ngắn. Trong bối cảnh của quang học phi tuyến, siêu ngắn xung laser được quan tâm vì hai lý do riêng biệt. Lý do đầu tiên là bản chất của sự tương tác quang phi tuyến thường thay. | Chapter 13 Ultrafast and Intense-Field Nonlinear Optics . Introduction There is currently great interest in the physics of ultrashort laser pulses. Recent advances have led to the generation of laser pulses with durations of the order of 1 attosecond. Ultrashort pulses can be used to probe the properties of matter on extremely short time scales. Within the context of nonlinear optics ultrashort laser pulses are of interest for two separate reasons. The first reason is that the nature of nonlinear optical interactions is often profoundly modified through the use of ultrashort laser pulses. The next two sections of this chapter treat various aspects of the resulting modifications of the nature of nonlinear optical interactions. The second reason is that ultrashort laser pulses tend to possess extremely high peak intensities because laser pulse energies tend to be established by the energy-storage capabilities of laser gain media and thus short laser pulses tend to have much higher peak powers than longer pulses. The second half of this chapter is devoted to a survey of the sorts of nonlinear optical processes that can be excited by extremely intense laser fields. . Ultrashort Pulse Propagation Equation In this and the following section we treat aspects of the propagation of ultrashort laser pulses through optical systems. Some physical processes that will be included in this analysis include self-steepening leading to optical shockwave formation the influence of higher-order dispersion and space-time cou 561 562 13 Ultrafast and Intense-Field Nonlinear Optics pling effects. In the present section we derive a form of the pulse propagation equation relevant to the propagation of an ultrashort laser pulse through a nonlinear dispersive nonlinear optical medium. In many ways this equation can be considered to be a generalization of the pulse propagation equation the so-called nonlinear Schrodinger equation of Section . We begin with the wave equation in the .